The performance requirements for semiconductor devices continue to increase. Performance may be improved, for example, with the addition of further input and output signal connections. To accommodate these additional connections in small surface mount packages, soldered grid array technology has been used and continues to develop. As one example, Bump/Ball Grid Arrays (BGAs) have conductive bumps/balls (e.g., solder and/or conductive-filled polymer) arranged in a conductive grid array pattern and serving as the connectors. This density is further increased in MicroBGAs (μBGA) and Chip Scale Packages (CSPs). As advantages, the higher density BGA reduces package size, and also helps lead to decreased printed circuit board (PCB) size, shorter leads/interconnections, reduced weight, improved electrical performance, and/or decreased cost.
With regard to gaining widespread use, both reliability of semiconductor packages and low cost of manufacture may help promote maximized package adoption/use. The BGA package conductive bumps/balls are the package's interface with the receiving substrate printed circuit board (e.g., PCB) upon which the BGA package is mounted. It has been found within research directed toward the present invention that the reliability of this interface can sometimes be affected by package standoff distance. If used between a PCB and a package, standoff distance may be, for example, the distance from the top plane of the PCB to the bottom edge of the BGA package after mounting. It has been found in the present research that the inability to control Surface Mount Technology (SMT) assembly deviations in standoff distance can lead to solder collapse and low cyclic fatigue life.
In addition to physical integrity, electrical performance is another consideration of conductive grid array (as well as any) mounting technology. More particularly, as system functions increase, package power demand (e.g., electrical current conduction) likewise may increase. Such current may be delivered through the PCB layers to the die through some of the conductive bumps/balls, but as they become smaller, the conductive bumps/balls may not be able to handle a required electrical current conduction capacity, or an excessive number of conductive bumps/balls may be required to do so. Further, other electrical components/functions (e.g., resistors, capacitors, inductors) may be required in the area proximate to the conductive grid array, which may place limits on the conductive grid array design.
Needed are arrangements to control semiconductor package standoff distance, and to provide convenient electrical functions.